2000 — Jan 31, Alaska Airlines Flight 261 Crash, Off Point Mugu, Ventura County, CA–88

—  88  Aircraft Crashes Record Office (Geneva, Switzerland). California 2000-2009. N963AS.

—  88  NTSB. “Board Meeting: Loss of Control and Impact with Pacific Ocean…” 12-10-2002.

—  88  Notable California Aviation Disasters. “The 2000s.” Oct 23, 2008 update.

 

Narrative Information

 

Notable California Aviation Disasters:

 

“Number 2 of California’s “10 Worst Crashes”

“Date / Time: Monday, January 31, 2000 / 4:21 p.m.

“Operator / Flight No.: Alaska Airlines / Flight 261

“Location: Off Point Mugu, Ventura County, Calif.

 

“Details and Probable Cause:   The Alaska Airlines McDonnell Douglas MD-83 (N963AS) was on a flight from Puerto Vallarta, Mexico, to San Francisco and scheduled to continue on to Seattle, Washington.

 

“While cruising at an altitude of 31,000 feet off the California coast, the aircraft suddenly dropped to 24,300 feet and the pilots radioed they were experiencing problems with the “stabilizer trim.”   The MD-83 then made a controlled descent to 18,000 feet, at which time the pilots requested to divert to and make an emergency landing at Los Angeles International Airport.

 

“The request was granted but shortly thereafter the jetliner plummeted again in an uncontrollable dive and plunged nose-first and inverted into the Pacific Ocean approximately 2.7 miles north of Anacapa Island.

 

“The crash, occurring just 11 minutes after the flight first reported a control problem, killed all 83 passengers and five crew members aboard the jetliner.

 

“The National Transportation Safety Board’s (NTSB) investigation of a possible faulty or unlubricated jackscrew assembly, which controls movement of the horizontal stabilizer mounted atop the MD-83’s vertical fin, continued through December of 2002.

 

“At that time, the NTSB determined that the probable cause of the accident was a loss of airplane pitch control, resulting from the in-flight failure of the horizontal stabilizer trim system’s jackscrew assembly — more precisely the failure of the assembly’s acme nut threads.   The thread failure, which led to a loss of control of the jetliner by the pilots, was caused by excessive wear resulting from Alaska Airlines’ insufficient lubrication of the jackscrew assembly.

 

“Contributing to the accident was Alaska Airlines’ extended lubrication interval at the time, and the Federal Aviation Administration’s approval of that extension, which increased the likelihood that an unperformed or inadequate lubrication would result in excessive wear of the acme nut threads; and Alaska Airlines’ extended routine check interval — and the FAA’s approval of that extension — which allowed the excessive wear of the acme nut threads to progress to the point of failure without the opportunity for detection.

 

“Also contributing to the accident was the absence of a fail-safe mechanism on MD-83 jetliners (and similar models of aircraft) to prevent the catastrophic effects of total acme nut thread loss.

 

“The worst aviation disaster in Ventura County history. Fatalities: 88.” (Notable California Aviation Disasters.  “The 2000s.” Oct 23, 2008 update.)

 

NTSB: “Executive Summary: On January 31, 2000, about 1621 Pacific standard time, Alaska Airlines, Inc., flight 261, a McDonnell Douglas MD-83, N963AS, crashed into the Pacific Ocean about 2.7 miles north of Anacapa Island, California. The 2 pilots, 3 cabin crewmembers, and 83 passengers on board were killed, and the airplane was destroyed by impact forces. Flight 261 was operating as a scheduled international passenger flight under the provisions of 14 Code of Federal Regulations Part 121 from Lic Gustavo Diaz Ordaz International Airport, Puerto Vallarta, Mexico, to Seattle-Tacoma International Airport, Seattle, Washington, with an intermediate stop planned at San Francisco International Airport, San Francisco, California. Visual meteorological conditions prevailed for the flight, which operated on an instrument flight rules flight plan.

 

Probable Cause: “The National Transportation Safety Board determines that the probable cause of this accident was a loss of airplane pitch control resulting from the in-flight failure of the horizontal stabilizer trim system jackscrew assembly’s acme nut threads. The thread failure was caused by excessive wear resulting from Alaska Airlines’ insufficient lubrication of the jackscrew assembly.

 

“Contributing to the accident were Alaska Airlines’ extended lubrication interval and the Federal Aviation Administration’s (FAA) approval of that extension, which increased the likelihood that a missed or inadequate lubrication would result in excessive wear of the acme nut threads, and Alaska Airlines’ extended end play check interval and the FAA’s approval of that extension, which allowed the excessive wear of the acme nut threads to progress to failure without the opportunity for detection. Also contributing to the accident was the absence on the McDonnell Douglas MD-80 of a fail-safe mechanism to prevent the catastrophic effects of total acme nut thread loss.

 

“The safety issues discussed in this report include lubrication and inspection of the jackscrew assembly, extension of lubrication and end play check intervals, jackscrew assembly overhaul procedures, the design and certification of the MD-80 horizontal stabilizer trim control system, Alaska Airlines’ maintenance program, and FAA oversight of Alaska Airlines. Safety recommendations are addressed to the FAA….” (NTSB. “Board Meeting: Loss of Control and Impact with Pacific Ocean, Alaska Airlines Flight 261, McDonnell Douglas MD-83, N963AS, about 2.7 miles north of Anacapa Island, California, January 31, 2000.” 12-10-2002.)

 

Sources

 

Aircraft Crashes Record Office (Geneva, Switzerland). California 2000-2009. Accessed 3-3-2009 at: http://www.baaa-acro.com/Pays/Etats-Unis/Californie-2000-2009.htm

 

Jones, Ray and Joe Lubow. Disasters and Heroic Rescues of California (Disasters and Heroic Rescues Series). Guilford, CT: Insiders’ Guide, an imprint of the Globe Pequot Press, 2006.

 

National Transportation Safety Board. “Board Meeting: Loss of Control and Impact with Pacific Ocean, Alaska Airlines Flight 261, McDonnell Douglas MD-83, N963AS, about 2.7 miles north of Anacapa Island, California, January 31, 2000.” 12-10-2002. Accessed 6-1-2015 at: http://www.ntsb.gov/news/events/Pages/Loss_of_Control_and_Impact_with_Pacific_Ocean_Alaska_Airlines_Flight_261_McDonnell_Douglas_MD-83_N963AS_about_2.7_miles_no.aspx

 

Notable California Aviation Disasters. “The 2000s.” Oct 23, 2008 update. Accessed 10-20-2009 at:  http://www.jaydeebee1.com/crash00s.html